Housing and manipulating apparatus for light modifying elements



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Feb. 11, 1958 L. cAPATosTo 2,822,729

Housmc AND MANIPULATING APPARA FOR LIGHT MODIFYING ELEMENTS 2Sheets-Sheet 1 Filed Sept. 1. 1953 ld///// /////f////// Feb- 11, 1958 L.cAPATos-ro 2,822,729

HOUSING AND MANIPULATING APPARATUS FOR LIGHT MODIFYING ELEMENTS FiledSept. 1. 1953 2 Sheets-Sheet 2 F/a4 '8 N E g 2| zo,

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INVENTOR, I9 27 LEO CAPA T0570.

A TTOR/VEX United States Patent O 'HOUSING AND MANIPULATING APPARATUSFOR LIGHT MODIFYING ELEMENTS Leo Capatosto, Brooklyn, N. Y., assignor tothe United tShtates of Americanas represented by the Secretary of e ArmyApplication September 1, 1953, Serial No. 377,988 2 Claims. (Cl. 88-111)(Granted under Title 35, U. S. Code (1952), sec. 266) The inventiondescribed herein may be manufactured and used by or for the Governmentfor governmental purposes without the payment of any royalty thereon.

This invention relates to a combination protecting inclosure andmanipulator device for a plurality of light controlling screens or thelike.

The invention provides complete protection for the filters or screenswhen not in use and incorporates an ecient selective manipulating meansfor removing the desired filter from its protecting case and positioningit in operating position. The manipulating means also functions toreplace the iilter in its case and to sequentially remove and replaceall of the filter units.

The device may briefly be described as follows. A protecting casing isprovided to contain a plurality of filter or masking units or the likefor use in various optical devices. Each of the units is arranged tomove smoothly into and out of the casing.

The complete device is light and compact having provision for securingit in operating position on the apparatus with which it is used, such asa photographic enlarger.

A mechanism is provided for moving a selected one of the filter units ora sequence thereof out of the casing into operative position and thenback into the casing by means of the simple turning of a knob. The knobis secured to a shaft having a number of cams thereon corresponding toor not less than the number of filter units. These cams engage followersurfaces of the filter holder units to swing them about a pivot intooperating position. The cam assembly has a gear thereon meshing withanother gear upon another shaft which carries a plurality of retractingcams which act upon another follower surface upon the filter holders tomove them back into their casing.

The cams may be relatively angularly positioned on their shafts toprovide direct sequential selection of filters or they may have anydesired arrangement.

It isa primary object of the invention to provide protection and readyaccessibility for a plurality of interchangeable light controllingaccessories or the like for optical apparatus.

A further object of the invention is to provide a protecting holder forthe accessories which is mounted directly upon the apparatus with whichit is to be used.

A still further object of the invention is to provide means for quicklyand accurately manipulating the accessories from storage position tooperating position one at a time or if desired in prearranged sequence.

Other objects and features of the invention will more fully appear fromthe following description and will be particularly pointed out in theclaims.

To present a better understanding of the invention a specific embodimentthereof will be described and illustrated in the accompanying drawingsin which Fig. 1 is a general view of the device in perspective; Fig. 2is a top plan view with portions of its casing broken away; Fig. 3 is afront elevation of the device partly in crosssection; Fig. 4 is avertical cross-section on line 4-4 Fig. 2; Figs. 5 and 6 are detailviews illustrating the shape of the cams used in the device.

The invention greatly increases the eiciency of operation of opticalapparatus wherein light modifying members such as filters, masks and thelike are to be inserted in a beam of light or interchanged from one toanother in the beam. It very often is required that a substantial numberof filters of varying values must be interchanged. The conventionalmethod has been, prior to the invention, to provide some sort of aholding device at the operating position of the filters and to manuallyand individually insert and remove the required filter in the holdingdevice.

This system presupposes that the operator will have conveniently at handthe required filter and that the visibility in the workroom is adequateto choose the correct one and to properly and quickly place the lter inits holder.

Obviously, the visibility in the room in which optical operationsinvolving filters is being conducted is not high and many times it isvery low. This is especially true in the darkroom wherein photographicoperations are conducted. The diiculty of locating, identifying andinserting the correct filter impairs the efficiency of the wholeoperation. The present invention reduces selection and replacement offilters to the simple turning of a single knob.

By way of example, the present invention will be described in connectionwith a photographic enlarging apparatus. In such an apparatus 'itbecomes necessary to insert light modifying partially transparentelements in the light beam of the apparatus. It may be desired to reducethe light intensity in which case one or more neutral density filtersare used. In the printing of color elements such as transparencies orcolor prints it is many times necessary to use filters of various colorsand density to exercise a desired control in the color balance of thefinal print. Color separation filters are also necessary in the makingof separation negatives and in the making of prints on the variablegamma type of printing paper wherein filters are used to control thecontrast of the prints.

In this type of apparatus, therefore, as well as in other opticaldevices it is for certain operations essential to use one or morefilters or masks to control the light. The device of the invention maybe constructed to contain any number of different filters or lightmodifying elements. As illustrated in the drawings the dust tight casing5 is designed to hold six dilerent filters. The filter material may beglass, sheet gelatin, sheet plastic or any appropriate substance. Thefilters, desirably, are held securely in holders 6 having apertures 7slightly smaller than the lter. The lilter is placed over the apertureand a clamping ring 8 is provided to secure the filter 9 in position.

The lter holders have a shank portion 10 in the outer end of which is anaperture within which is received a pivot pin 11. The outer extremity ofthe shank 10 beyond the aperture has formed thereon a pair of angularlydisposed faces 12 and 13 which are engaged by cams to cause the filterto be respectively projected from and retracted into the casing S in amanner to be described.

Desirably, the casing has a removable cover portion 14 securely fastenedto its main section. The holders 6 are arranged one above the other withtheir ends containing the lters situated at one end of the casing. Theholders are pivotally supported upon the pivot pin 11 to freely swinginto and out of the casing thru an opening 15 in the side thereof.Desirably, the holders 6 are spaced from each other slightly by spacingwashers.

Special means Aare provided to move the filters in and out of thecasing. The mechanism for manipulating the filters and their holderscomprises a pair of parallel shafts 16 and.17 rotatably mounted in thecasing 5 the shafts having respectively groups of cams 18 and 19 securedthereon. The shafts are connected by a pair of intermeshing gears 20 and21 havin-g a driving ratio of one to one. One of the shafts, for examplethe shaft 16, has an extension outside of the casing and has securedthereon a manually operable knob 22 by means of which the shafts 16 and17 are rotated.

The structure of and the manner in which the cams 18 and 19 coact withthe holders 6 will now be described. One group of cams are designed toeject the holders while the other group retracts them. In each casethere are the same number of cams on the shafts as there are filters,each cam acting upon one only of the filters. The cams 18 on shaft 16consist of a circular hub portion thru which the shaft extends and asubstantially radially extending narrow tooth-like cam portion shown inFig. 5. The cams are angularly spaced a convenient amount as for example54 which leaves a space of 88 which may be the spacing between thenumber one cam and the last cam. Each cam is positioned axially alongits shaft in position to coincide with the plane of the respectiveholder 6 it is to operate.

The cams upon the shaft 17 are arranged similarly to those on shaft 16,each cam being positioned in a plane coinciding with the plane of theholder it is to actuate. The cams 19 are also angularly spaced 54. Eachof the cams 19 have the shape shown in Fig. 6. They are made from a discof metal having a cut out portion at 23 and of a thickness substantiallythe same as the shank 10 of the holders. The cut out portion is cutinward from its periphery along a line 24 diagonal to a tangent drawn atthe periphery of the disc thus forming a hook-like portion 25. The line24 meets a line 25 at substantially right angles thereto. Y The line 25is parallel to and spaced outwardly from a radius of the cam. The cutout then follows generally the curvature of the hub portion 26 thereofand thence extends outward to the periphery along a radius 27 parallelto the line 25. All of the cams are alike and are spaced angularly abouttheir axis of rotation the same as the cams 18. The exact shape of thecut out 23 is not critical and may have any form which will function inthe manner set forth hereinafter.

The pivot pin 11 is so positioned that the faces 12 and 13 on the filterholders are situated in the position shown in Fig. 2 wherein the face 13is adjacent to the face 28 of one of the cams 18 while the lobe of theend portion of the filter holder presenting the face 12 is entirelyremoved from the cutaway portion 23 of the corresponding retracting cam19.

The relative position of the parts above described exists when all ofthe filters are within the casing 5. Assuming it is desired to eject thetopmost filter the knob 22 is rotated counterclockwise. The topmost ofthe cams 18 as viewed in Fig. 2 will then engage the face 13 of the topfilter holder and cause it to swin-g its filter out of the casing andinto operating position as shown in dotted lines Fig. 2. In the specificapplication of the invention described herein this extend positionplaces the filter upon the axis of the lens 29 of an enlarging apparatusas shown in Fig. l.

At this time it will be noted that the face 12 of the holder and theface 24 of the top cam 19 have moved substantially into contact sincethe shaft 17 is rotated clockwise by its gear 21. Also the cam 18 isabout to clear the periphery of the portion of the filter holderpresenting the face 13. Thus the topmost filter is placed in operatingposition. If desired this position may be accurately located by means ofa click stop device to be described hereinafter.

If it is desired to replace the filter or to substitute anothertherefor, the knob 22 is again rotated counterclockwise. When the face24 engagestheface 12 the filter and holder are swung back into thecasing where it is stopped by a bumper 30 desirably having a rubbercovering to absorb the shock of contact. At this time the second cam 18from the top has arrived at a position ready to engage the face 12 ofthe second filter holder from the top so that further rotation of theknob will eject the second filter. By further rotation of the knob 22the second filter will be retracted until it engages the bumper 30 whenit is again within the protection of the casing 5.

By continued rotation of the knob 22 any one of the filters may beplaced in operating position. An important feature of the invention inthis connection is its use in the sequential operation of a series offilters such as in the case where three color filters are used in themaking of separation negatives. In this operation the three filters arearranged sequentially within the casing and they are Ibrought intooperation by successive partial rotations of the knob. Under the dimlight permissible or in total darkness manipulation of the filtersbecomes a simple, fast and accurate operation.

To further enhance the operation of the device, a click stop or othersimilar means is employed to indicate the completion of each filterpositioning operation. To accomplish this result means are associatedwith the knob 22. The knob is hollowed out to present a cup shape whichfits loosely over a boss 31 extending outward from the casing 5 and thruthe center of which the shaft 16 extends. A set screw 32 secures theknob to the shaft. A hole 33 is formed near the periphery of the boss 21within which is received a spring 34 which engages and urges a steelball 35 into one of a plurality of depressions 36. The depressions aresix in number corresponding to the six filter holders and are angularlyspaced to correspond to the spacing of the cams. The position of theknob upon the shaft is adjusted so that the ball will enter the firstdepression when the number one filter is projected and will enter theother depressions successively as the other filters arrive at theiroperating positions. Thus the friction imposed by the spring and ballserves to guide the operator in accurately selecting and positioning anyfilter even in total darkness. By knowing the position of each filter inthe casing from a given reference point, such as with respect to thetopmost one, the operator may readily select any desired filter byrotating the knob thru the required number of ejecting cycles.

As shown in Fig. l the device is adapted to be secured to the apparatuswith which it functions. Such attachment may be permanent or readilyseparable. As shown, a 'bracket 37 is fixed to the body of the enlargingapparatus the lower end of which is provided with an attachingthumbscrew 38. Desirably a thumb screw 38 has threaded engagement withand acts to clamp the casing 5 to the bracket. The parts are so arrangedthat when a filter has been ejected from the casing its center will beupon the optical axis of the lens 29.

vAs shown in Fig. 1 the front wall 40 of the casing i may convenientlybe used for inscribng the identification of each filter, the respectiveinscriptions being placed on the wall in line with the filteridentified.

The cams may be secured in fixed angular relation and to theirrespective gears in any desired manner. One manner of accomplishing thisend is shown in Fig. 4. In this construction a pair of locking pins 41are driven thru drilled holes in each cam and in the associated gear.

What is claimed is: l

l. A housing and manipulating device for a plurality of lightcontrolling screens comprising a casing to inclose said screens,carriers to hold said screens pivoted about a common axis to swing intoand out of said casing, a plurality of ejecting cams fixed to a shaftparallel to said axis, a corresponding plurality of retracting cams.fixed to another parallel shaft, follower means on each Y the cam shaftssimultaneously in opposite directions.

2. A housing and manipulating device for light controlling screenscomprising a casing to inclose the screens having an opening to permitthe screens to be moved out of the casing, a plurality of carriers forsaid screens presenting cam follower surfaces, a pivot shaft in saidcasing upon which said carriers are independently pivoted in differentplanes, a pair of parallel cam shafts mounted in said casing parallel tosid pivot shaft, a plurality of cams fixed together on each shaft equalin number to the number of said carriers, the said cam follower surfaceson each carrier being disposed to engage the cam faces of a pair of camsoppositely disposed on 6 said shafts, successive cams along said shaftshaving4 their cam faces disposed in angularly spaced positions to actsuccessively and independently to move said carriers out .of and intosaid casing and means for rotating the cams on each shaft simultaneouslyin opposite directions.

References Cited in the lile of this patent UNITED STATES PATENTS917,368 Seidel Apr. 6, 1909 1,552,920 Glover Sept. 8, 1925 2,151,735Bresser Mar. 28, 1939 2,627,207 Bell Feb. 3, 1953 2,660,926 Talley Dec.1, 1953 FOREIGN PATENTS 435,220 Great Britain Sept. 17, 1935 847,244Germany Aug. 21, 1952

